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Inverter for an electronic ballast having independent start-up and operational output voltages

  • US 5,747,942 A
  • Filed: 07/10/1996
  • Issued: 05/05/1998
  • Est. Priority Date: 07/10/1996
  • Status: Expired due to Fees
First Claim
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1. An electronic ballast for energizing a gas-discharge lamp, the electronic ballast comprising:

  • a square-wave amplifier having a square-wave amplifier input and a square-wave amplifier output;

    a lamp control circuit including an oscillator;

    the oscillator oscillating at any oscillator frequency within an entire oscillator frequency range during a start-up mode of the lamp, the lamp control circuit providing a signal at the oscillator frequency to the square-wave amplifier input;

    a resonant circuit coupled to the square-wave amplifier output;

    the resonant circuit having a resonant frequency, a relative frequency difference between the oscillator frequency and the resonant frequency determining the luminance of the lamp during an operational mode of the lamp;

    a step-up transformer having a primary winding and a secondary winding;

    the primary winding receiving electromagnetic energy from the square-wave amplifier output;

    a ratio of primary winding turns to secondary winding turns selected to provide a transformer secondary voltage that equals or exceeds a start-up threshold voltage of the lamp, the ratio depending upon a transformer primary voltage.

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